Chapter 3- Synapses Flashcards
synapse
specialized gaps/ junctions between neurons used to communicate by transmitting chemicals
reflexes
automatic muscular response to stimuli
reflex arc
the circuit from sensory neurons to muscle response (the speed of conduction)
temporal summation
repeated stimuli within a brief time having a cumulative effect
presynaptic neuron
the neuron that delivers that synaptic transmission
postsynaptic neuron
the neuron that receives the message
excitatory postsynaptic potential
a graded depolarization that occurs when Na+ ions enter the postsynaptic neuron
spatial summation
synaptic input from several locations exerting a cumulative effect and trigger a nerve impulse
inhibitory postsynaptic potential
the temporary hyperpoalrization of a membrane (occurs when K+ leaves the cell or Cl- enters the cell after it is stimulated)
spontaneous firing rate
the ability to produce action potentials without synaptic input (esps increase above the rate; isps decrease below the rate)
neurotransmitters
chemicals that travel across the synapse and communicate between neurons )released by one neuron and affect another)
amino acids
acids containing an amine group (NH2)
neuropeptides
chains of amino acids (polypeptide - protein)
acetylcholine
a chemical similiar to amino acid replaced by a N(CH3)3 group
monoamines
neurotransmitters containing an amine group formed by a metabolic change of amino acid
cathecholamines
compounds containing a catechol and an amine group (dopamine, epinephrine, norepinephrine)
tryptophan
precursor for serotonin
vesicles
tiny spherical packets that store high concentrations of neurotransmitters near the presynaptic (held for release)
MAO (monamine oxidase)
a chemical that breaks down excess levels of some neurotransmitters into inactive chemicals
exocytosis
(neurotransmitter release) the excretion of the neurotransmitter from the presynaptic terminal into the synaptic cleft
triggered by an action potential arriving from the axon
ionotropic effect
when a neurotransmitter attaches to receptors and immediately opens ion channels
transmitter gated/ ligand gated channels
channels of sodium and potassium along an axon , controlled by a neurotransmitter
metabotropic effects
when neurotransmitters attach to a receptor and initiates a sequence of slower and longer lasting metabolic reactions